Determining How Much Wall Paint You Need

By Gene Hamilton, Katie Hamilton

Part of Home Improvement For Dummies Cheat Sheet

To avoid having too much leftover wall paint, use these formulas to determine how much paint to buy when you start your home improvement painting project.

Total Wall Area:

[Total Length of All Walls] × [Wall Height] = Total Wall Area

Unpainted Areas:

[Window Height] × [Window Width] × [Number of Windows] = Window Area

[Door Height] × [Door Width] × [Number of Doors] = Door Area

Paintable Wall Area:

[Total Wall Area] – [Window Area] – [Door Area] = Paintable Area

Paint to Order:

[Paintable Area] ÷ 350 = Number of Gallons Needed for Smooth Walls

[Paintable Area] ÷ 300 = Number of Gallons Needed for Rough, Textured Walls or Unpainted Wallboard